A method of reinforcing pipe coatings

ABSTRACT

Reinforcement for pipe coatings comprising helically wound reinforcing wire imbedded in the pipe coating material and a plurality of relatively short, elongated wires or rods extending longitudinally of the pipe and transverse to the helical windings. The rods are spaced apart circumferentially of the pipe and are initially held in place in the coating material by the helical windings. The rods may be projected onto the coating material simultaneously with the application of the coating and with the application of the helically wound reinforcing wire. Alternatively, the rods can be carried onto the coating with the helical windings. In another embodiment, the rods are attached to a pair of spaced apart, elongated wires so that the pre-formed rod and wire assembly may be wound on the pipe during the coating operation.

United States Patent [191 Werner METHOD OF REINFORCING PIPE COATINGS Arthur D. Werner, 6303 Kury, Houston, Tex. 77008 [22] Filed: May 6, 1971 [21] Appl. No.: 140,655

[76] Inventor:

[52] US. Cl. 264/228, 138/175, 138/176,

264/271, 264/309, 425/110, 425/111 [51] Int. Cl B281) 1/32 [58] Field of Search 264/228, 271;

[56] References Cited UNITED STATES PATENTS 2,191,025 2/1940 Mitchell 264/228 2,696,353 12/1954' Vessels 264/228 1,966,725 7/1934 Kraner 264/271 Sept. 25, 1973 Primary Examiner-Donald .1. Arnold Assistant Examiner-T. E. Balhoff Attorney-Bradley (It Wharton 57 ABSTRACT Reinforcement for pipe coatings comprising helically wound reinforcing wire imbedded in the pipe coating material and a plurality of relatively short, elongated wires or rods extending longitudinally of the pipe and transverse to the helical windings. The rods are spaced apart circumferentially of the pipe and are initially held in place in the coating material by the helical windings.

The rods may be projected onto the coating material simultaneously with the application of the coating and with the application of the helically wound reinforcing wire. Alternatively, the rods can be carried onto the coating with the helical windings. In another embodiment, the rods are attached to a pair of spaced apart, elongated wires so that the pre-formed rod and wire assembly may be wound on the pipe during the coating operation.

6 Claims, 4 Drawing Figures PAH-INTER $925973 Arihur D. Werner INVENTOR.

ATTORNEYS.

. METHOD OF REINFORCING PIPE COATINGS This invention relates to the coating of pipe and, more particularly, to a method and apparatus for reinforcing pipe coatings.

Antibouyancy weight coatings are conventionally applied to pipe joints which are to be installed in underwater pipelines. These coatings usually comprise one or more layers of heavy concrete. The concrete is sprayed or projected at high velocity against the pipe as the latter is both rotated and translated past the coating station.

A reinforcement is provided for the concrete coating, primarily to hold the concrete in place until it has set or hardened. A continuous wire wound helically on the pipe and imbedded in the concrete coating during the coating operation has been used for this reinforcement. Such a continuous elongated wire can be applied to the pipe simultaneously with the application of the concrete coating and has the distinct advantage of economies of application and flexibility in the choice of wire, size suitable for a particular coating.

Pipe coaters have been forced, however, to discontinue use of the elongated, continuous, simple wire reinforcement for coatings of this kind despite their advantages. Helical windings of wire of this kind do not provide adequate reinforcement for the concrete between the adjacent convolutions of the windings.

The reinforcement is applied and imbedded in the material as the concrete is projected against the pipe to build up the desired coating. Thus, the pipe is both rotated and translated longitudinally of the pipe during this coating operation. It would be difficult, if not impossible, to apply continuous reinforcement wires running longitudinally of the pipe, during the coating operation, especially in view of the rotation of the pipe on its longitudinal axis.

Accordingly, coaters have been forced to discontinue the use of the continuous single wire, helical wound reinforcements despite their obvious advantages in many other respects. Instead, they have resorted to the use of elongated strips of woven wire mesh reinforcements which are wound on the pipe helically during the coating operation. This type of prefabricated wire mesh (commonly called key mesh") must be woven in advance of application, and is therefore much more costly than single strand wire. Further, because of the weaving or forming operation, the maximum diameter for the wire use in fabricating the mesh is limited. The use of relatively small diameter wire for this purpose usually dictates that the wire be protected by galvanizing or other means to insure that sufficient reinforcement strength remains in the wire after it has been exposed to weathering and other deteriorating agencies. This obviously greatly adds to the cost of the mesh reinforcement which is already expensive as a result of the fabricating operation.

Equipment to fabricate the wire mesh is not universally available. This often requires the expenditure of substantial amounts to ship rolls of prefabricated mesh to the coating site when such mesh is not locally available. This is particularly a problem in overseas coating operations since many foreign countries do not have facilities for producing the mesh reinforcement. On the other hand, rolls of continuous, single strand wire are widely available and in substantially any size desired for coating reinforcement purposes. The diameter chosen for such wire is not limited by the maximum size which can be handled by mesh forming machines, and the size can be large enough to provide the desired strength allowing for anticipated deterioration.

It is, therefore, an object of the present invention to provide pipe coating reinforcing structure and a method of applying the same wherein generally conventional wire stock can be utilized, thereby avoiding the expense of specially manufactured wire mesh.

It is another aim of the invention to provide structure and a method for enhancing the reinforcement provided to pipe coatings of this type by helically wound, single strand reinforcement wire.

Still a further object of the invention is to provide a method and structure whereby the economies and advantages associated with the use of continuous, single strand wire may be achieved in this field without the disadvantages which have heretofore been associated with pipe coating reinforcement of this kind.

These and other aims and objects of the invention will be further explained or will become apparent from the claims, specification and drawing.

In the drawing:

FIG. 1 is a top plan view of a joint of pipe undergoing application of a coating simultaneously with placement of the reinforcing structure of the invention;

FIG. 2 is a vertical cross-sectional view through the joint of pipe taken along line 2-2 of FIG. 1;

FIG. 3 is a greatly enlarged fragmentary crosssectional view taken along line 3--3 of FIG. 2; and

FIG. 4 is a top plan view, similar to FIG. 1, showing a modified form of the reinforcement structure of the invention.

Referring initially to FIG. 1 of the drawing, a joint of pipe 10 is advanced past a coating station 12 where a heavy aggregate coating material M such as concrete is projected on the surface of the pipe by the action of a rotating brush l6 and a conveyor 18 (FIG. 2). As is well known by those skilled in the art, it is the practice to support the pipe 10 at either end by a pair of rollers 20 which rotate the pipe about its longitudinal axis while an appropriate carriage (not shown) advances the pipe longitudinally in the direction of the arrow in FIG. ll. This assures application of a uniform coating throughout the length of the pipe 10. Translation or advancement of the pipe during the coating operation causes the material 14 to build up at an angle relative to the surface of the pipe 10. This presents a frustoconical surface 22 at the zone of application. The surface 22 merges into a planar surface 24 as the pipe 10 advances.

A thrower 26 having a storage hopper 28 and a projecting head 30 is positioned above the pipe 10 for delivering relatively short, rigid, elongated reinforcing elements in the nature of rods or lengths of wire 32 to the coating 14 on the surface of the pipe. Each of the rods 32 may be identical and they can be formed from readily available steel or wire stock in any length desired. The length should be sufficient that at least two adjacent convolutions of helically wound reinforcing wire traverse each rod as will be subsequently described. It is preferable, however, that the length of the rods 32 not exceed the transverse dimension of the surface 22 to assure that the rods will not project beyond the surface 24, although in those cases where the pipe 10 is to be coated in a multiple pass operation longer lengths for the rods 32 can be utilized and may even be desirable.

The rods 32 are projected onto the surface 22 and are immediately imbedded into the coating 14 as the latter continues to build up. The rods 32 should be projected onto the coating 14 at a slight angle relative to the surface of the pipe so as to be parallel to the surface 22. This prevents voids in the coating material around and beneath the rods and assures maximum compaction of the material 14. The rods 32 are disposed around the entire circumference of the pipe 10 as the latter rotates and is advanced longitudinally in a circumferentially spaced, continuous helical configuration.

Simultaneously with application of the generally longitudinally oriented rods 32 to the coating, helical convolutions of reinforcement wire are wound around the pipe and imbedded in the coating. In the embodiment of apparatus to accomplish the invention shown in FIGS. 1 and 2 of the drawing, three spools 34 are disposed immediately above the coating station 12 and adjacent the rod thrower 26 for supplying continuous lengths of three members such as wires or lines 36. The reinforcing lines 36 are wound circumferentially around the pipe 10 to traverse the rods 32. It is desirable to have at least two of the lines 36 cross each rod 32 and they may cross at the respective ends of the rods with a third line at approximately the center of the rods. Thus, the lines 36 cooperate with the rods 32 to provide what may be considered to be a plurality of reinforcing bands 38 disposed generally in end-to-end relationship along the length of the pipe. The spacing and rod lengths may be selected so that the rods of one band 38 are intermediate the rods of an adjacent band 38 and the one band overlaps the adjacent band.

The rods 32 are projected onto the coating material as the lines 36 are wound onto the pipe and the timing is such that the material and lines bind the rods into place in the coating almost immediately after the rods impinge against surface 22. It may also be desirable in some cases to provide a more or less conventional warping mechanism, illustrated schematically and designated by the numeral 40, to interweave the rods with the lines 36 prior to application so that the rods are drawn with the lines onto the pipe. The warping action of the mechanism 40 results in every other rod 32 projected from the head 30 being disposed intermediate the center line 36 and the two end lines 36 as best illustrated in FIG. 3. The under and over relationship of the center line 36 to the rods 32 which is accomplished by the warping action serves to unite the composite bands 38 and facilitates retention of the rods on the surface 22. In certain instances, however, it may be desirable to simply wind each of the lines 36 over the rods 32 without the benefit of the warping action and resulting interwoven effect.

It will be appreciated that the reinforcing structure presented by the bands 38 imbedded in the coating 14 can be formed from rods 38 and tie lines 36 of considcrably larger diameter than the diameter of wire heretofore used in forming wire mesh. Thus it is not necessary to galvanize either the lines 36 or the rods 32 to protect them from rust since normal amounts of rust or similar deterioration can be tolerated without danger of substantially weakening the reinforcing structure. Both the wire tie lines 36 and the rods 32 can be selected from conventional readily available stock and it is contemplated that in certain applications it will be desirable to form the rods 32 into the desired lengths immediately prior to depositing them onto the coating 14. This could be accomplished by apparatus similar to conventional nailing machines where nails are formed from wire stock as they are used by the machine.

Manifestly, the invention also contemplates a method of reinforcing a pipe coating with a plurality of reinforcing rods extending longitudinally of the pipe and a plurality of reinforcing lines extending circumferentially around the pipe. The method includes the steps of rotating the pipe and moving it longitudinally during the coating operation while the rods 32 are placed in circumferentially spaced relationship by projecting the rods onto the coating 14 and oriented generally longitudinally of the pipe 10. Simultaneously, the lines 36 are wound circumferentially around the pipe to traverse the rods 32 and present a plurality of interconnected continuous reinforcing bands 38.

Of primary importance in performing the method of this invention is the provision of the longitudinally oriented wires or rods into position for enhancing the reinforcement afforded by the helically wound wires. Further, one or a plurality of helically wound wires may be used.

An alternative form of carrying out the invention is illustrated in FIG. 4 wherein a pipe joint 10 is again moved longitudinally of a coating station 12 for application of a coating material 14, in the same manner as previously described for the embodiment of FIGS. 13. In the embodiment of FIG. 4, however, the rod thrower 26 is eliminated and a spool 42 is disposed above the coating station 12, with both the rods 32 and the wire tie lines 36 wound therearound. The rods 32 are secured to the tie lines 36 by appropriate spot welds or the like at the ends of each of the rods 32. Only two of the lines 36 are utilized in the example shown, it being recognized that additional line might be used if deemed desirable. One of these lines is secured to the rods 32 with a degree of slack to accommodate winding of the reinforcement assembly on surface 22 and the resulting increased circumferential spacing between the outermost ends of the rods because of the frusto-conical configuration of surface 22. The slack in wire 36 disposed to ultimately expand to provide the convolution of'greatest diameter can be accommodated by simply bending the wires between successive rods so that the composite assembly may be wound on a rod or spool for convenient handling prior to use. Tension on the bent wire straightens the bends to expand that side of the assembly as the reinforcement is drawn relatively taut onto the frusto-conical surface 22 by rotation of the pipe.

The the rods 32 and tie lines 36 are placed on the coating 14 in the alternative embodiment by simply unwinding the spool 42 in a helical configuration to present a plurality of end-to-end, circumferential reinforcing bands 38 along the length of the pipe 10. Again, the rods 32 are placed on the coating 14 at an angle corresponding to the angle of application of the coating so that the rods lie essentially flat on surface 22.

What is claimed is:

l. A method of reinforcing a coating on the outer surface of a pipe, comprising:

projecting a coating material onto the outer surface of the pipe; placing a plurality of elongated elements into disposition to support the coating material while said material is on the pipe, said placing step occurring simultaneously with said projecting step, with the elements oriented generally longitudinally of the pipe and spaced apart circumferentially of the pipe; and p winding one or more elongated reinforcement members helically around the elements and the coating material in a series of spaced apart convolutions extending longitudinally of the pipe, with at least one convolution engaging each element to hold the latter into said supporting disposition with respect to the coating material.

2. The method as set forth in claim 1, wherein is included the step of winding at least two convolutions of said member about each element.

3. The method as set forth in claim 2, wherein is included the step of rotating and translating the pipe simultaneously with application of said coating material and said reinforcement.

4. The method as set forth in claim 3, wherein said reinforcing member and elements are imbedded in said coating material during application of the elements, members and coating material to the pipe.

5. The method as set forth in claim 1, wherein said placing step comprises projecting said elements individually longitudinally of the pipe and onto at least a portion of said coating material.

6. A method of reinforcing a coating on the outer surface of a pipe, utilizing a reinforcing material comprising a plurality of elongated elements and a plurality of reinforcing members coupled with said elements and extending transversely thereof, said method comprising the steps of:

projecting a coating material onto the outer surface of the pipe; simultaneously winding said reinforcing material around the pipe in a helical configuration with said elongated elements oriented generally longitudinally of the pipe and spaced apart circumferentially of the pipe; and

tensioning said reinforcing members to draw the latter taut around the outer surface of the pipe as said reinforcing material is wound around the pipe whereby said reinforcing material at least partially supports said coating material on the surface of the pipe. 

1. A method of reinforcing a coating on the outer surface of a pipe, comprising: projecting a coating material onto the outer surface of the pipe; placing a plurality of elongated elements into disposition to support the coating material while said material is on the pipe, said placing step occurring simultaneously with said projecting step, with the elements oriented generally longitudinally of the pipe and spaced apart circumferentially of the pipe; and winding one or more elongated reinforcement members helically around the elements and the coating material in a series of spaced apart convolutions extending longitudinally of the pipe, with at least one convolution engaging each element to hold the latter into said supporting disposition with respect to the coating material.
 2. The method as set forth in claim 1, wherein is included the step of winding at least two convolutions of said member about each element.
 3. The method as set forth in claim 2, wherein is included the step of rotating and translating the pipe simultaneously with application of said coating material and said reinforcement.
 4. The method as set forth in claim 3, wherein said reinforcing member and elements are imbedded in said coating material during application of the elements, members and coating material to the pipe.
 5. The method as set forth in claim 1, wherein said placing step comprises projecting said elements individually longitudinally of the pipe and onto at least a portion of said coating material.
 6. A method of reinforcing a coating on the outer surface of a pipe, utilizing a reinforcing material comprising a plurality of elongated elements and a plurality of reinforcing members coupled with said elements and extending transversely thereof, said method comprising the steps of: projecting a coating material onto the outer surface of the pipe; simultaneously winding said reinforcing material around the pipe in a helical configuration with said elongated elements oriented generally longitudinally of the pipe and spaced apart circumferentially of the pipe; and tensioning said reinforcing members to draw the latter taut around the outer surface of the pipe as said reinforcing material is wound around the pipe whereby said reinforcing material at least partially supports said coating material on the surface of the pipe. 